-LRB- CNN -RRB- -- The bad economy and downturn in the housing market are n't the only painful things for Realtor Anne Stephens . Her knees , hips and ankles hurt from arthritis .

Anne Stephens , 61 , was in her late 30s when she was diagnosed with osteoarthritis .

`` I ca n't sit too long . I ca n't stand too long , and I ca n't walk too long , '' said Stephens , 61 , from Conyers , Georgia .

Stephens is among the 27 million Americans who suffer from the most common form of arthritis called osteoarthritis .

`` I think people tend to think of this as more of a nuisance , '' said Dr. John Klippel , president and CEO of the Arthritis Foundation . `` They think of it as only aches and pains and not the serious problem that it actually is -- the leading cause of disability in this country . ''

Klippel said part of the misconception has to do with all the myths surrounding the disease .

Common myth 1 : Arthritis is a disease of the elderly

While older people do develop arthritis , children and teenagers can get certain forms of the condition , Klippel said .

The Arthritis Foundation reports two-thirds of people with doctor-diagnosed arthritis are under age 65 . Watch more on arthritis fact and fiction ''

Stephens was in her late 30s when she developed osteoarthritis after injuring her knees running and playing volleyball .

She felt a sharp pain and recalled , `` It was downhill after that . ''

Researchers do n't know the exact cause of arthritis , but they do know what puts people at risk .

Klippel said that while the disease is associated with aging , other risk factors include heredity , joint injury , obesity and lack of fitness .

Common myth 2 : Cracking your knuckles causes arthritis

Despite what your grandmother told you , experts say cracking your knuckles is not a risk factor for arthritis .

`` It 's annoying -- it 's certainly not good for the joints , but on the other hand , it does n't cause arthritis , '' Klippel said .

Common myth 3 : Predicting the weather

`` Boy , there 's a good myth , '' Klippel said with a chuckle . `` I ca n't tell you how many patients I would take care of who would say they were better than the weatherman at predicting changes in humidity . ''

He said researchers have studied the claims , but concluded there is no scientific evidence to suggest arthritis flare-ups occur during bad weather .

Klippel also does n't buy the argument that arthritis patients are better off if they live in a warmer climate .

`` If you live in a warmer climate , you 're simply more active for more months of the year and that 's probably why people feel better , '' Klippel said . `` It probably has very little to do with the weather itself . ''

Common myth 4 : Exercise aggravates arthritis

Staying active actually is one of the most important ways to prevent and ease the pain of arthritis , Klippel said . It also helps with weight control .

`` For people with arthritis , it hurts to exercise , '' he said . `` But over time , the post-exercise pain actually diminishes if you push through it . ''

He recommended choosing joint-friendly exercises such as walking , biking or swimming .

In addition to putting ice on an aching joint , Klippel suggested taking nonsteroidal , anti-inflammatory medication before or after exercising to help relieve the pain .

`` People need to stay active and move their joints to keep the muscles strong and to keep the joints flexible , '' Klippel said .

Common myth 5 : Nothing helps

Klippel worries about arthritis patients who do n't seek medical help because they do n't think anything can be done about the pain .

He said a proper diagnosis can lead to a host of possible treatments , including the latest prescription medicines for pain and rehabilitating aching joints through physical therapy .

Klippel urges people not to wait until the pain is unbearable before seeing a doctor .

`` If aches and pains persist for more than four weeks , that 's a time to pay attention , '' he said .

Anne Stephens followed that advice and she said it has made all the difference . She manages the inflammation and pain by taking prescription medication -LRB- a nonsteroidal anti-inflammatory drug -RRB- . She also exercises at least three days a week ; the workouts help her strengthen her muscles . And she sees her doctor several times a year .

`` I 've learned to adapt , '' she said . `` I know what 's going to hurt me and what does n't . ''

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Osteoarthritis , the most common form of the disease , affects 27 million Americans

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Arthritis is not a disease of the old : Two-thirds of those diagnosed are under 65

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Prescription and over-the-counter drugs can help with pain , as can exercise